Adolescents who frequently lash out at others may be setting the stage for long-term physical health challenges, according to research published by the American Psychological Association. The study suggests that aggressive behaviour in early adolescence is not merely a social or emotional concern, but may also carry biological consequences that emerge years later. In particular, researchers found that higher levels of aggression during the teenage years were associated with faster biological ageing and a higher body mass index (BMI) by the age of 30, pointing to a potential link between early interpersonal difficulties and later-life health outcomes.
Lead author Joseph Allen, PhD, of the University of Virginia, emphasised the broader implications of these findings. He noted that the study sheds light on how social challenges during formative years may have enduring effects on physical well-being. Accelerated biological ageing, he explained, has been linked in previous research to an increased risk of conditions such as coronary artery disease, diabetes, hypertension, chronic inflammation, and even premature mortality. These connections underscore the importance of understanding how early behavioural patterns may influence long-term health trajectories.
The study, published in the journal Health Psychology, followed a cohort of 121 adolescents—46 males and 75 females—from both suburban and urban communities in the southeastern United States. Beginning at age 13, participants were tracked into adulthood through a comprehensive, multi-informant approach. Researchers gathered self-reported measures of aggression, alongside parent-reported levels of family conflict and peer evaluations of relationship behaviours. This longitudinal design allowed for a nuanced examination of how early social dynamics evolve and relate to later biological outcomes.
When participants reached age 30, researchers assessed biological ageing using a set of blood-based biomarkers. These included indicators such as C-reactive protein, blood glucose levels, and white blood cell counts, among others. By applying a sophisticated algorithm that integrates these 12 markers, the researchers generated an estimate of each individual’s biological age. This measure, Allen noted, often provides a more accurate prediction of future health and mortality risk than chronological age alone, offering a deeper insight into the body’s physiological condition.
To ensure robustness, biological ageing was evaluated using two established methods: the Klemera-Doubal approach and PhenoAge. Both methods incorporate a range of physiological indicators—including blood pressure, inflammation, cholesterol, glucose regulation, and immune function—to estimate how “old” a person’s body appears biologically. Across both measures, the findings were consistent: individuals who exhibited higher levels of aggression in early adolescence tended to show more advanced biological ageing by age 30. Importantly, these associations remained significant even after accounting for factors such as gender, socioeconomic status, early illness, and adolescent body composition.
Further analyses revealed that the pathway from early aggression to accelerated ageing was not direct, but instead operated through ongoing relationship difficulties. Males and individuals from lower-income backgrounds were more likely to exhibit faster biological ageing, patterns that appeared linked to higher levels of relational conflict—such as strained parent-child interactions or punitive peer behaviour. Crucially, early aggression alone did not predict later ageing unless it persisted in the form of chronic interpersonal problems. These findings suggest that the lasting health impact may stem less from isolated behaviours and more from enduring patterns of conflict. While the study does not establish causation, it highlights the importance of supporting adolescents in developing healthier relationships, which may have benefits extending well beyond emotional well-being to influence long-term physical health.
More information: Joseph Allen et al, Predictions from early adolescent interpersonal aggression to accelerated aging in adulthood: Relational and biological mechanisms of linkage, Health Psychology. DOI: 10.1037/hea0001576
Journal information: Health Psychology Provided by American Psychological Association
